In this type of situation, ideally he would go straight to his veterinarian for surgery to remove the fish hook, or better yet, straight to a specialty hospital that has endoscopy set-up (thin flexible camera), where he would be anesthetized, and the camera would be placed into his stomach though his mouth to see if the fish hook can be removed that way, avoiding surgery. However, endoscopy may not be available in your area. Are there any emergency veterinarians on call at night?
If not, the next best thing is to do what you have done already. Feed him (kibble mixed with water), and a total of 4-5 slices of thin sandwich bread. After he finishes, pick up the food and do not offer any more food. Water is OK. Take him to his veterinarian first thing tomorrow morning, and they will take an x-ray to see if the fish hook is still in the stomach or if it appears to be moving through. Check his bowel movements in the morning to see if it has already passed.
I hope it all turns out OK for him!!! Please let me know how everything turns out. I have done surgery twice for dogs with fish hooks in the stomach- and everything turned out OK, but they were brought right in after it happened. The food and bread will hopefully cushion the sharp point of the hook, so that it doesn't cause damage.
Do you have any other questions for me at this time?